This document describes the use of spectra collected from ore froth to predict properties of froth quality and properties of the ore from which the froth was produced for example froth color, solid to bitumen ratio, froth ore processability, fines content, and total bitumen content, and to use this information in process control. This disclosure describes flotation implementation and collection of spectra, the preprocessing of spectra, the spectra features sensitive to each of the three properties and the related predictive models, and implementation of the method.
The separability of bitumen from oil sand depends on a number of factors. Some of these factors are observable using reflectance spectrometry. This document describes bitumen recovery performance tests conducted using a Denver cell for water flotation of aerated bitumen froth under a standard set of operating conditions. Further, hyperspectral measurements of ore samples and oil froth are described. Features associated with bitumen, quartz, and clay readily visible in samples and in the froth at the surface of the cell are described. We disclose the use of spectral information to predict the total bitumen content, fines content, solid to bitumen ratio and processability of ore samples, the relationship of these variables to froth colour, and the techniques of classifying froth types using spectra.
Naturally occurring oil sand may be a mixture of quartz grains, clay minerals, bitumen, and water. Bitumen recovery performance, termed processability (ore processability being the expected fraction of product material that may be separated using a particular separation circuit—a measure of the expected recovery of product material for a particular process), may depend on bitumen content, types and amounts of clays present, degree of weathering of the ore before processing, and process conditions for a given process configuration. As ore deposits are not homogeneous and ore may display considerable variability in clay, bitumen, water and fines, which impact the bitumen recovery and processability, there is a need for a robust method to characterize processability of incoming feed stock in near real-time prior to reaching the plant.
The high-precision (≦0.5%) determination of total bitumen content (TBC) in oil sand ore is typically conducted by traditional analytical approaches that are time consuming (several hours per sample). Infrared reflectance spectroscopy has been used in a number of oil sand studies to investigate for example variations in oil sand slurry, the mineralogy of oil sands, bitumen characteristics, and bitumen content in ground ore. In past studies [1], [2] we used reflectance spectra of oil sands to generate predictive models of total bitumen content and fines content. This work discloses by contrast, the relationship between spectral properties of oil sand ore froth and observations of ore processability, to assist in improving the processability of the incoming feedstock ore in real time before it enters the extraction plant.